In a large saucepan cook onion in hot oil until tender but not brown. Add uncooked rice; cook and stir for 1 minute. Slowly add chicken broth. Bring to boiling; reduce heat. Cover; simmer for 15 to 20 minutes or until rice is tender and liquid is absorbed. Stir in feta cheese, mint, and pepper. Serve warm. If desired, garnish with fresh mint leaves. Makes 6 side-dish servings.